[Clinical and molecular cytogenetic features of myeloid diseases characterized by i(20q-): a study of seven cases]

To investigate the clinical and molecular cytogenetic features of myeloid diseases characterized by i(20q-).

The clinical data of 7 patients with myeloid diseases, 6 with myelodysplastic syndrome (MDS) and one with acute myelocytic leukemia (AML), 4 males and 3 females, aged 51 - 74, were analyzed. Chromosome specimens were prepared by direct method and/or short-time culture of bone marrow cells. Karyotyping was performed by R banding technique. Two kinds of probes (20q subtelomere probe and 20q12 unique sequence probe) were used in dual-color fluorescence in situ hybridization (D-FISH) assay.

Of the seven patients, 4 died and 3 survived by the end of this study. The patients survived for 6 months (case 1), 7 months (case 2), 17 days (case 4), and 28 days (case 5) respectively. Karyotype analysis showed that one of the normal chromosomes 20 was lost and substituted by one or two small metacentric isochromosomes smaller than the normal chromosome 20 in all these seven cases. It was proved to be ider(20)(q10) del(20)(q11q13), i(20q-) in six cases by D-FISH assay.

i(20q-) is a novel and rare recurrent chromosome abnormality which may be specifically associated with myeloid diseases and poor prognosis.